Interaction Between5-HTTLPR And Stress Predicts Depressive Symptoms:A Multi-wave Longitudinal Study

Object (1) To investigate whether Serotonin Transporter Gene Promoter Region Polymorphism (5-HTTLPR) is directly associated with depressive symptoms of adolescents:(2) To investigate interaction between5-HTTLPR and stressful life events in predicting depressive symptoms.Methods A total of252students were selected randomly from a public high school in Changsha and were conducted9times follow-up assessments during2years. At initial assessment, all the participants completed Center for Epidemiological Studies Depression Scale (CES-D) and Adolescent Life Events Questionnaire (ALEQ) to assess depressive symptoms and life events.5ml of venous blood of each participant was collected during the initial assessment to extract genomic DNA and identify5-HTTLPR genotype. Every participant completed CES-D and ALEQ every three months for the subsequent2years. Hierarchical Linear Model (HLM) was used for statistical analyses.Results The results of HLM analyses indicated:(1) the main effects of stress were significant both in males (β-0.14, p<0.0001) and females (β=0.13, p<0.0001);(2) No significant main effect of 5-HTTLPR was found either in males (β=0.21,p>0.05) or in females (β=1.16, p>0.05);(3) among females, a significant cross-level interaction between5-HTTLPR and stress emerged (β=0.08,p<0.0001), females with at least one5-HTTLPR S allele exhibited higher depressive symptoms in relation to stress; however, no significant interaction appeared in males (β=-0.03,p>0.05).Conclusion5-HTTLPR is not directly associated with depressive symptoms of adolescents. Interaction between5-HTTLPR and stress can predict depressive symptoms in female adolescents, but cannot predict depressive symptoms in male adolescents.